1. Field of the Invention
The present invention relates to a motorized pulley with a cable connector.
2. Description of the Related Art
Motorized pulleys are known in a number of contexts and are used ie material handling equipment, including roller conveyors and endless conveyor belts, packaging systems, logistic systems for goods and luggage and check-out counters.
EP 0 752 970 B1 teaches a motorized pulley having an integral electrical connector at the end of the shaft and for being connected to an electric power source. The motorized pulley comprises a cylindrical drum which is rotatably mounted on a stationary roller shaft. An electric motor and a gear are arranged within the drum and are connected to the shaft for producing rotation of the drum about the shaft. At the end of the shaft, a recess is provided for receiving a connector assembly that is electrically coupled to the electric motor. The connector is configured as a cylindrical plug device and has a diameter larger than the diameter of the recess at the end of the shaft, whereby a compression occurs of the connector when it is inserted into the cylindrical recess.
At each end of the shaft a shaft pin is provided exteriorly of the part of the shaft that extends outside the drum and thus covers same. The shaft pin serves to secure the motorized pulley to the support (eg the frame of a conveyor belt) to the effect that reaction forces (the torque) can be transplanted thereto. Each shaft pin is secured to the shaft by means of a screw or pin that is taken through the shaft pin and down into the shaft.
The one shaft pin has a square opening at the one end and is intended for being secured on the shaft end where the cable connector is configured. In this context the square opening serves for insertion of a female connector to the cable connector (the male connector) in order to thereby establish a power supply for the motorized pulley. The female connector is of a particular type that requires very little space for mounting. This is advantageous since, very often, there is not much space available for supporting cable connectors and wiring. The motorized pulley is advantageous in that it enables expedient and simple electric coupling of the motorized pulley. Subsequently the female connector is secured to the shaft cap by means of a screw, whereby a connection is established that will not readily be able to “vibrate” apart. The mounting and exchange, if any, of the motorized pulley can therefore be performed expediently and in a simple manner.
However, in some particular cases problems occur in that large production tolerances occur in the individual parts (cable connector (male connector)/female connector and shaft cap). When the parts are subsequently assembled, ie when the male connector is mounted in the recess in the shaft end and the shaft cap is subsequently mounted thereon, the production tolerances in the individual parts express themselves in that the overall tolerances in the shaft with the mounted cable connector become even quite high. Thereby the problem occurs of conveying the female connector through the opening in the shaft cap and engaging the female connector and the cable connector (the male connector), and finally securing the female connector reliably to the shaft cap by means of the fastening screw. In these particular cases it may involve that the parts must be forced together with ensuing damage to the individual parts, including the cable connector. In other particular cases the tolerances have a magnitude preventing the female connector from being conveyed through the hole in the shaft cap and establishing the conductive coupling with the cable connector, nor can it be secured reliably by means of the fastening screw to the shaft cap.
Of course, this is inconvenient and involves that a number of combinations of cable connectors and female connectors must be tried to find the combination where the tolerances in cable connection and female connection are within acceptable values. In connection with the manufacture of the motorized pulley this combination task can be performed with some difficulty, but in those cases where an already installed motorized pulley is to be exchanged, eg in connection with a renovation task, it will be practically impossible to have to test one's way through various motorized pulleys until the correct combination of cable connector and female connector is found. Alternatively the connector must be forcibly compressed with an ensuing risk of damaging connector and its conductors. It is therefore the object of the invention to provide a motorized pulley with a cable connector whereby the problems associated with the prior art are obviated.